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Application Notes

Circuits from the Lab

New Product Briefs

Technical Articles

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Power Management Home

Application Notes

AN-1306: ADP1050 and ADP1051 EEPROM Programming and Calibration in the Power Supply Manufacturing Environment

This 11-page Application Note specifies the EEPROM programming and calibration for the ADP1050 and ADP1051 digital controllers for isolated power supplies during power supply manufacturing. First, the hex file used for EEPROM programming is generated by the GUI software in the power supply development stage. Second, using the generated hex file, the EEPROM can be programmed. Finally, the calibration procedure is presented.

AN-1253: Layout Considerations for Digital Power Management (ADP1046A)

The ADP1046A secondary side digital power controller features analog-to-digital converters, integrated I2C communication, analog comparators, and digital compensation. Layout is crucial for complex mixed signal devices with closely spaced input and output functions, so proper care must be taken to avoid hazards. This 7-page Application Note provides guidelines to avoid noise coupling and techniques for proper grounding.

AN-1213: Powering the AD9788 800 MSPS TxDAC Digital-to-Analog Converter Using the ADP2105 Synchronous Step-Down DC-to-DC Regulator for Increased Efficiency

This 3-page Application Note describes a circuit that uses a pair of ADP2105 synchronous step-down dc-to-dc regulators to provide the individual power supply rails required for the AD9788 dual channel, 16-bit, high dynamic range TxDAC digital-to-analog converter at greater than 85% efficiency.

AN-1211: Powering the AD9268 Dual Channel 16-Bit, 125 MSPS Analog-to-Digital Converter with the ADP2114 Synchronous Step-Down DC-to-DC Regulator for Increased Efficiency

This 3-page Application Note describes a circuit that uses the ADP2114 dual channel synchronous step-down dc-to-dc regulator to provide the individual power supply rails required for the AD9268 dual 16-bit, 125 MSPS, 1.8 V ADC at 85% efficiency.

AN-1210: Powering the AD9272 Octal Ultrasound ADC/LNA/VGA/AAF with the ADP5020 Switching Regulator PMU for Increased Efficiency

This 4-page Application Note describes a circuit that uses the ADP5020 power management unit to provide the individual power supply rails required for the AD9272 octal LNA/VGA/AAF/ADC and crosspoint switch.

Circuits from the Lab

CN0280: Robust Completely Isolated Current Sense Circuit with Isolated Power Supply for Solar Photovoltaic Converters

This completely isolated current sensor with isolated power source is highly robust and can be mounted close to the sense resistor for accurate measurements and minimum noise pickup. The 16-MHz output data stream from a sigma-delta modulator is processed by a DSP using a SINC3 digital filter. Ideal for monitoring the ac current in solar photovoltaic (PV) converters, the circuit can handle peak ac voltages of several hundred volts and currents between a few mA and 25 A.

Fully Isolated Lithium Ion Battery Monitoring and Protection System (CN0235)

Lithium ion (Li-Ion) battery stacks contain a large number of individual cells that must be monitored correctly in order to enhance the battery efficiency, prolong the battery life, and ensure safety. The 6-channel AD7280A devices in this circuit act as the primary monitor, providing accurate voltage measurement data to the System Demonstration Platform (SDP-B) evaluation board; the 6-channel AD8280 devices act as the secondary monitor and protection system. Both devices can operate from a single wide supply range of 8 V to 30 V and operate over the industrial temperature range of −40C to +105C. The AD7280A contains an internal 3-ppm reference that allows a cell voltage measurement accuracy of 1.6 mV. The ADC resolution is 12 bits and allows conversion of up to 48 cells within 7 μs. The AD8280 functions independently of the primary monitor and provides alarm functions, indicating out of tolerance conditions. It contains its own reference and LDO, both of which are powered from the battery cell stack. The reference, in conjunction with external resistor dividers, is used to establish overvoltage/undervoltage trip points. Each channel contains programmable deglitching circuitry to avoid alarming from transient input levels. The AD7280A and AD8280, which reside on the high voltage side of the battery management system, have a daisy-chain interface, allowing up to eight AD7280As and eight AD8280s to be stacked together and 48 Li-Ion cell voltages to be monitored. Adjacent AD7280As and AD8280s can communicate directly, passing data up and down the stack without the need for isolation. The master devices on the bottom of the stack use the SPI interface and GPIOs to communicate with the SDP-B evaluation board. High-voltage galvanic isolation is required to protect the low-voltage side of the SDP-B board at this interface. The ADuM1400 and ADuM1401 digital isolators and the ADuM5404 digital isolator with integrated dc-to-dc converter combine to provide the required eleven channels of isolation in a compact, cost effective solution. The ADuM5404 also provides isolated 5 V to the VDRIVE input of the lower AD7280A and the VDD2 supply voltage for the ADuM1400 and ADuM1401 isolators.

New Product Briefs

June 2014

Dual 3-MHz, 800-mA Buck Regulators

adp5133The ADP5133 combines two high-performance buck regulators in a tiny package to meet demanding performance requirements. Their high switching frequency enables the use of tiny multilayer external components, minimizing PCB area. The buck regulators can operate in forced PWM mode, or can switch to power save mode (PSM) when the load current falls below the threshold, improving light-load efficiency. The two bucks operate out of phase to reduce the input capacitor size and noise. The regulators are activated through dedicated enable pins; and the output voltages can be externally set through a resistor feedback network. Operating on a single 2.3-V to 5.5-V supply, the ADP5133 draws 87 A with all channels enabled and 0.3 A with all channels disabled. Available in a 16-ball WLCSP package, it is specified from 40C to +125C and priced at $1.29 in 1000s.

May 2014

Low-cost precision Analog Front End and Controller for testing and monitoring battery cells

ad8451The AD8451 precision analog front end and controller for testing and monitoring battery cells includes a precision fixed-gain instrumentation amplifier (IA) that measures the batterys charge/discharge current and a fixed-gain difference amplifier (DA) that measures the batterys voltage. Internal laser trimmed resistor networks set the IA gain to 26 and the DA gain to 0.8, optimizing performance over the rated temperature range. The device simplifies designs by providing high accuracy, low drift over temperature, flexibility, and high reliability in a space-saving package. Voltages at the ISET and VSET inputs set the desired constant current and constant voltage values. Switching between these modes is automatic and transparent to the system. The MODE input selects between charge and discharge modes; and the VCTRL output interfaces directly with PWM controllers, such as the ADP1972. Operating on 15-V and +5 V supplies, the AD8451 dissipates 240 mW. Available in an 80-lead, 14-mm 14-mm 1 mm LQFP package, it is specified from 40C to +85C and priced at $5.40 in 1000s.

Dual 1-A, 18-V Synchronous Step-Down Regulator with fail-safe voltage monitoring

adp2311The ADP2311 fully integrated, dual output, synchronous step-down dc-to-dc regulator operates from input voltages between 4.5 V and 18 V and regulates output voltages down to 0.6 V. Each channel can provide up to 1 A of continuous output current. Integrated high-side and low-side MOSFETs provide a very high efficiency, compact solution. The two channels run 180 out of phase to reduce the input ripple current and input capacitor size, thereby helping to lower system electromagnetic interference (EMI). Integrated internal compensation and soft start circuitry simplifies the design. An on-chip watchdog timer can reset the microprocessor if it fails to strobe within a preset timeout period. Accurate voltage monitoring circuitry and a power fail comparator provide a controlled power-up and power-down sequence to enhance system reliability. The robust design includes undervoltage lockout (UVLO), overvoltage protection (OVP), overcurrent protection (OCP), and thermal shutdown (TSD). Available in an 24-lead, LFCSP package, it is specified for a 40C to +125C junction temperature and priced at $2.38 in 1000s.

High-efficiency Integrated Power Solution for multicell lithium-ion applications

adp5080The ADP5080 fully integrated, high-efficiency power solution for multicell lithium-ion battery applications can connect directly to the battery, eliminating the need for preregulators and increasing the battery life. It integrates two keep-alive LDO regulators, five synchronous buck regulators, a configurable buck-boost regulator, and a high-voltage LDO regulator. The highly integrated power solution incorporates all power MOSFETs, feedback loop compensation, voltage setting resistors, discharge switches, and a charge pump that generates a global bootstrap voltage. These features minimize the number of external components and PCB area, providing significant advantages for portable applications. Switching frequencies from 750 kHz to 2 MHz are selectable on each channel. Key functions such as soft start, selectable preset output voltage, and flexible power-up and power-down sequences are programmable via the I2C interface with fused factory defaults. Available in a 72-ball WLCSP package, the ADP5080 is specified from 25C to +85C and priced at $4.39 in 1000s.

Technical Articles

Jess Espiritu, Complex Power-Supply Sequencing Made Easy, Analog Dialogue, 2014-06-04

Irvin Ou, Simple Circuit Allows Backward Compatibility for Digital Power Controllers, Analog Dialogue, 2014-05-05

David Rice, Dynamic power control minimises power loss, maximises temperature range, EE Times Europe, 2014-04-16

David Rice, Dynamic power control minimises power loss, maximises temperature range, EDN Europe, 2014-04-16

Frederik Dostal, Digital power management without code qualification, Power Systems Design, 2014-03-03

Glenn Morita, Noise-Reduction Network for Adjustable-Output Low-Dropout Regulators, Analog Dialogue, 2014-03-03

Maurice O'Brien, Integrated Power Management Unit Simplifies FPGA-Based System, Electronics Maker, 2013-12-28

Maurice O'Brien, Highest Power Density, Multi-Rail Power Solution For Space-Constrained Applications, Analog Dialogue, 2013-11-01

Frederik Dostal, Power Management for Health Care Applications, Power Systems Design, 2013-10-17

Xing Xing, N.X. Sun, and Baoxing Chen, High-Bandwidth Low-Insertion Loss Solenoid Transformers Using FeCoB Multilayers, IEEE Transactions on Power Electronics, 2013-09-01

Webinars and Tutorials

Galvanic Isolation for Power Supply Applications -- This seminar discusses isolation and isolation technologies in terms of signal transmission methods and isolation materials, including optocouplers and digital isolators. Ii covers isolation usage, including current sensing, gate driver, and communication functions in ac-to-dc, motor control, hybrid electrical vehicles, PV, and other power supply applications.

Solving Isolation Challenges in Power Conversion Applications - This webcast will present solutions to isolation challenges in power conversion applications. Among the topics to be discussed are the limitations of traditional methods of isolation (such as utilization of optocouplers and pulse transformers) vs. more efficient and cost effective solutions that utilize digital isolators. If you are currently using optocouplers and pulse transformers, this is a webcast you should attend.

Design Techniques for reducing power consumption and harmful thermal events in industrial designs - This webcast will present: typical analog module configuration and how to calculate the maximum ambient temperature that the system can tolerate, new technology to reduce the power dissipated in the module (regardless of what output load is connected), and the performance of these devices when the supply is run from a switching regulator rather than with a linear regulator.

Fundamentals of Designing with Semiconductors: Powering Your Circuit - What is important about a power supply and how does it work? What different types of power supplies and conversion methods are used? How can a power supply affect the signal chain and how do you select the best regulator for your circuit? This webcast will also explain noise, ripple, line and load regulation, power supply rejection ratio, the effects of temperature change, and other specifications that impact power supply performance.

 

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